1. Field of the Invention
This invention relates to an outside air conditioner, and more particularly to an outside air conditioner for a clean room.
2. Description of the Related Art
FIG. 1 shows a flow diagram of an example of a conventional outside air conditioner. Referring to FIG. 1, the conventional outside air conditioner shown includes a heating coil 1 for heating outside air, mean temperature gauge 2 for measuring a mean temperature of outside air, air washer 3 for removing dust form outside air, cooling coil 4, heating coil 5, fan 6 for discharging supplied outside air to the outside, circulating pump 7, piping 8, outside air intake opening 9 for taking in outside air, and circulating water tank 10.
In the conventional outside air conditioner, outside air taken in through outside air intake opening 9 is heated to a temperature equal to or higher than 10.degree. C. by heating coil 1 under the control of mean temperature gauge 2. Then, the outside air is cleaned and humidified by air washer 3, and then the temperature and humidity of the outside air are adjusted by cooling coil 4 and heating coil 5, and thereafter the outside air is supplied into a room by fan 6.
While, in the conventional outside air conditioner, duct is removed by air washer 3, air washer 3 does not exhibit a high dust removal efficiency for vaporized impurities of nitrogen oxides and sulfur oxides in the form of gas since water sprayed from air washer 3 has a room temperature. Particularly in manufacturing semiconductors, since very small objects are handled, impurities in the air such as nitrogen oxides and sulfur oxides may have a bad influence on the yield of products, and there are problems in the use of outside air conditioners in an environment where semiconductors are manufactured.
Further, while, in the conventional outside air conditioner, sprayed water is consumed in the humidification of air, and excess water remains in a circulating water tank 10. Since the temperature of the water staying in circulating water tank 10 has a room temperature, micro-organisms, which propagate in the water of room temperatures, such as legionella pneumophila, may possibly propagate in the water.